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spi: pxa2xx: Introduce __lpss_ssp_update_priv() helper
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In a few places we repeat RMW IO operations on LPSS private
registers. Let's introduce a helper to make the code better
to read and maintain.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20250116162109.263081-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Andy Shevchenko authored and Mark Brown committed Jan 16, 2025
1 parent 9a8afbe commit 78b435c
Showing 1 changed file with 40 additions and 48 deletions.
88 changes: 40 additions & 48 deletions drivers/spi/spi-pxa2xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,8 +73,9 @@ struct chip_data {
#define LPSS_CAPS_CS_EN_MASK (0xf << LPSS_CAPS_CS_EN_SHIFT)

#define LPSS_PRIV_CLOCK_GATE 0x38
#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_OFF 0x0

struct lpss_config {
/* LPSS offset from drv_data->ioaddr */
Expand Down Expand Up @@ -321,6 +322,20 @@ static void __lpss_ssp_write_priv(struct driver_data *drv_data,
writel(value, drv_data->lpss_base + offset);
}

static bool __lpss_ssp_update_priv(struct driver_data *drv_data, unsigned int offset,
u32 mask, u32 value)
{
u32 new, curr;

curr = __lpss_ssp_read_priv(drv_data, offset);
new = (curr & ~mask) | (value & mask);
if (new == curr)
return false;

__lpss_ssp_write_priv(drv_data, offset, new);
return true;
}

/*
* lpss_ssp_setup - perform LPSS SSP specific setup
* @drv_data: pointer to the driver private data
Expand All @@ -337,21 +352,16 @@ static void lpss_ssp_setup(struct driver_data *drv_data)
drv_data->lpss_base = drv_data->ssp->mmio_base + config->offset;

/* Enable software chip select control */
value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
value &= ~(LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH);
value |= LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH;
__lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
value = LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH;
__lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, value, value);

/* Enable multiblock DMA transfers */
if (drv_data->controller_info->enable_dma) {
__lpss_ssp_write_priv(drv_data, config->reg_ssp, 1);
__lpss_ssp_update_priv(drv_data, config->reg_ssp, BIT(0), BIT(0));

if (config->reg_general >= 0) {
value = __lpss_ssp_read_priv(drv_data,
config->reg_general);
value |= LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE;
__lpss_ssp_write_priv(drv_data,
config->reg_general, value);
value = LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE;
__lpss_ssp_update_priv(drv_data, config->reg_general, value, value);
}
}
}
Expand All @@ -361,65 +371,47 @@ static void lpss_ssp_select_cs(struct spi_device *spi,
{
struct driver_data *drv_data =
spi_controller_get_devdata(spi->controller);
u32 value, cs;
u32 cs;

if (!config->cs_sel_mask)
cs = spi_get_chipselect(spi, 0) << config->cs_sel_shift;
if (!__lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, config->cs_sel_mask, cs))
return;

value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);

cs = spi_get_chipselect(spi, 0);
cs <<= config->cs_sel_shift;
if (cs != (value & config->cs_sel_mask)) {
/*
* When switching another chip select output active the
* output must be selected first and wait 2 ssp_clk cycles
* before changing state to active. Otherwise a short
* glitch will occur on the previous chip select since
* output select is latched but state control is not.
*/
value &= ~config->cs_sel_mask;
value |= cs;
__lpss_ssp_write_priv(drv_data,
config->reg_cs_ctrl, value);
ndelay(1000000000 /
(drv_data->controller->max_speed_hz / 2));
}
/*
* When switching another chip select output active the output must be
* selected first and wait 2 ssp_clk cycles before changing state to
* active. Otherwise a short glitch will occur on the previous chip
* select since output select is latched but state control is not.
*/
ndelay(1000000000 / (drv_data->controller->max_speed_hz / 2));
}

static void lpss_ssp_cs_control(struct spi_device *spi, bool enable)
{
struct driver_data *drv_data =
spi_controller_get_devdata(spi->controller);
const struct lpss_config *config;
u32 value;
u32 mask;

config = lpss_get_config(drv_data);

if (enable)
lpss_ssp_select_cs(spi, config);

value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
if (enable)
value &= ~LPSS_CS_CONTROL_CS_HIGH;
else
value |= LPSS_CS_CONTROL_CS_HIGH;
__lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
mask = LPSS_CS_CONTROL_CS_HIGH;
__lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, mask, enable ? mask : 0);
if (config->cs_clk_stays_gated) {
u32 clkgate;

/*
* Changing CS alone when dynamic clock gating is on won't
* actually flip CS at that time. This ruins SPI transfers
* that specify delays, or have no data. Toggle the clock mode
* to force on briefly to poke the CS pin to move.
*/
clkgate = __lpss_ssp_read_priv(drv_data, LPSS_PRIV_CLOCK_GATE);
value = (clkgate & ~LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK) |
LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON;

__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, value);
__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, clkgate);
mask = LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK;
if (__lpss_ssp_update_priv(drv_data, LPSS_PRIV_CLOCK_GATE, mask,
LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON))
__lpss_ssp_update_priv(drv_data, LPSS_PRIV_CLOCK_GATE, mask,
LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_OFF);
}
}

Expand Down

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